﻿#region "Copyright"
/*       Copyright (c) 2002 Douglas Crockford  (www.crockford.com) 
 
Permission is hereby granted, free of charge, to any person obtaining a copy of 
this software and associated documentation files (the "Software"), to deal in 
the Software without restriction, including without limitation the rights to 
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies 
of the Software, and to permit persons to whom the Software is furnished to do 
so, subject to the following conditions: 
 
The above copyright notice and this permission notice shall be included in all 
copies or substantial portions of the Software. 
 
The Software shall be used for Good, not Evil. 
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 
SOFTWARE. 
*/
#endregion


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace DarkLakeTools.JSUtility
{
    /// <summary>
    /// JavaScript Minify
    /// </summary>
    public class JSMin
    {
  
        const int EOF = -1;  
  
        StreamReader sr;  
        StringWriter sw;  
        int theA;  
        int theB;  
        int theLookahead = EOF;

        /// <summary>
        /// Minifies the specified JavaScript.
        /// </summary>
        /// <param name="src">The Source JavaScript.</param>
        /// <returns></returns>
        public string Minify(string src) 
        {
            byte[] bytes = ASCIIEncoding.ASCII.GetBytes(src);
            Stream stream = new MemoryStream(bytes); 

            using (sr = new StreamReader(stream))  
            {  
                
                using (sw = new StringWriter())  //used to be a StreamWriter  
                {  
                    jsmin();  
                    return sw.ToString(); // return the minified string  
                }  
            }  
        }  
  
        /* jsmin -- Copy the input to the output, deleting the characters which are 
                insignificant to JavaScript. Comments will be removed. Tabs will be 
                replaced with spaces. Carriage returns will be replaced with linefeeds. 
                Most spaces and linefeeds will be removed. 
        */  
        void jsmin()  
        {  
            theA = '\n';  
            action(3);  
            while (theA != EOF)  
            {  
                switch (theA)  
                {  
                    case ' ':  
                        {  
                            if (isAlphanum(theB))  
                            {  
                                action(1);  
                            }  
                            else  
                            {  
                                action(2);  
                            }  
                            break;  
                        }  
                    case '\n':  
                        {  
                            switch (theB)  
                            {  
                                case '{':  
                                case '[':  
                                case '(':  
                                case '+':  
                                case '-':  
                                    {  
                                        action(1);  
                                        break;  
                                    }  
                                case ' ':  
                                    {  
                                        action(3);  
                                        break;  
                                    }  
                                default:  
                                    {  
                                        if (isAlphanum(theB))  
                                        {  
                                            action(1);  
                                        }  
                                        else  
                                        {  
                                            action(2);  
                                        }  
                                        break;  
                                    }  
                            }  
                            break;  
                        }  
                    default:  
                        {  
                            switch (theB)  
                            {  
                                case ' ':  
                                    {  
                                        if (isAlphanum(theA))  
                                        {  
                                            action(1);  
                                            break;  
                                        }  
                                        action(3);  
                                        break;  
                                    }  
                                case '\n':  
                                    {  
                                        switch (theA)  
                                        {  
                                            case '}':  
                                            case ']':  
                                            case ')':  
                                            case '+':  
                                            case '-':  
                                            case '"':  
                                            case '\'':  
                                                {  
                                                    action(1);  
                                                    break;  
                                                }  
                                            default:  
                                                {  
                                                    if (isAlphanum(theA))  
                                                    {  
                                                        action(1);  
                                                    }  
                                                    else  
                                                    {  
                                                        action(3);  
                                                    }  
                                                    break;  
                                                }  
                                        }  
                                        break;  
                                    }  
                                default:  
                                    {  
                                        action(1);  
                                        break;  
                                    }  
                            }  
                            break;  
                        }  
                }  
            }  
        }  
        /* action -- do something! What you do is determined by the argument: 
                1   Output A. Copy B to A. Get the next B. 
                2   Copy B to A. Get the next B. (Delete A). 
                3   Get the next B. (Delete B). 
           action treats a string as a single character. Wow! 
           action recognizes a regular expression if it is preceded by ( or , or =. 
        */  
        void action(int d)  
        {  
            if (d <= 1)  
            {  
                put(theA);  
            }  
            if (d <= 2)  
            {  
                theA = theB;  
                if (theA == '\'' || theA == '"')  
                {  
                    for (; ; )  
                    {  
                        put(theA);  
                        theA = get();  
                        if (theA == theB)  
                        {  
                            break;  
                        }  
                        if (theA <= '\n')  
                        {  
                            throw new Exception(string.Format("Error: JSMIN unterminated string literal: {0}\n", theA));  
                        }  
                        if (theA == '\\')  
                        {  
                            put(theA);  
                            theA = get();  
                        }  
                    }  
                }  
            }  
            if (d <= 3)  
            {  
                theB = next();  
                if (theB == '/' && (theA == '(' || theA == ',' || theA == '=' ||  
                                    theA == '[' || theA == '!' || theA == ':' ||  
                                    theA == '&' || theA == '|' || theA == '?' ||  
                                    theA == '{' || theA == '}' || theA == ';' ||  
                                    theA == '\n'))  
                {  
                    put(theA);  
                    put(theB);  
                    for (; ; )  
                    {  
                        theA = get();  
                        if (theA == '/')  
                        {  
                            break;  
                        }  
                        else if (theA == '\\')  
                        {  
                            put(theA);  
                            theA = get();  
                        }  
                        else if (theA <= '\n')  
                        {  
                            throw new Exception(string.Format("Error: JSMIN unterminated Regular Expression literal : {0}.\n", theA));  
                        }  
                        put(theA);  
                    }  
                    theB = next();  
                }  
            }  
        }  
        /* next -- get the next character, excluding comments. peek() is used to see 
                if a '/' is followed by a '/' or '*'. 
        */  
        int next()  
        {  
            int c = get();  
            if (c == '/')  
            {  
                switch (peek())  
                {  
                    case '/':  
                        {  
                            for (; ; )  
                            {  
                                c = get();  
                                if (c <= '\n')  
                                {  
                                    return c;  
                                }  
                            }  
                        }  
                    case '*':  
                        {  
                            get();  
                            for (; ; )  
                            {  
                                switch (get())  
                                {  
                                    case '*':  
                                        {  
                                            if (peek() == '/')  
                                            {  
                                                get();  
                                                return ' ';  
                                            }  
                                            break;  
                                        }  
                                    case EOF:  
                                        {  
                                            throw new Exception("Error: JSMIN Unterminated comment.\n");  
                                        }  
                                }  
                            }  
                        }  
                    default:  
                        {  
                            return c;  
                        }  
                }  
            }  
            return c;  
        }  
        /* peek -- get the next character without getting it. 
        */  
        int peek()  
        {  
            theLookahead = get();  
            return theLookahead;  
        }  
        /* get -- return the next character from stdin. Watch out for lookahead. If 
                the character is a control character, translate it to a space or 
                linefeed. 
        */  
        int get()  
        {  
            int c = theLookahead;  
            theLookahead = EOF;  
            if (c == EOF)  
            {  
                c = sr.Read();  
            }  
            if (c >= ' ' || c == '\n' || c == EOF)  
            {  
                return c;  
            }  
            if (c == '\r')  
            {  
                return '\n';  
            }  
            return ' ';  
        }  
        void put(int c)  
        {  
            sw.Write((char)c);  
        }  
        /* isAlphanum -- return true if the character is a letter, digit, underscore, 
                dollar sign, or non-ASCII character. 
        */  
        bool isAlphanum(int c)  
        {  
            return ((c >= 'a' && c <= 'z') || (c >= '0' && c <= '9') ||  
                (c >= 'A' && c <= 'Z') || c == '_' || c == '$' || c == '\\' ||  
                c > 126);  
        }  

    }
}
